1. Field of the Invention
The present invention relates to a camera including a recording and playback device to record magnetic information on a magnetically recordable film and to play back the recorded information, and, more particularly, the present invention relates to a camera having a shielding member to shield a magnetically recordable film from magnetic flux generated by a drive motor.
2. Description of the Related Art
Cameras are known which are capable of recording photographic information for each film frame, such as a date of photography or an exposure value, on a magnetically recordable medium which is applied on the film. The photographic information recorded on the magnetically recordable medium applied on the film is read at a photography laboratory and the recorded information is printed on the back side of the prints.
In the known type of camera, the film is fed by driving a film winding spool with a drive motor placed inside the film winding spool. When a magnetically recordable film is used in the known camera having a drive motor inside the film winding spool, the recorded magnetic information may be damaged by magnetic flux leaked from the brush side of the drive motor, or playback may be hindered as a result of regenerated noise caused by the leaked magnetic flux. To prevent the magnetic flux from leaking from the film winding spool, a camera having a magnetic shield applied to the winding spool has been proposed. For example, Japanese Laid-Open Patent Publication No. H4-26832 discloses such a camera. Further, a camera having a permalloy material, or layers of permalloy material, used as a magnetic shield to reduce the magnetic noise from the motor has been proposed. For example, Japanese Laid-Open Patent Publication No. H5-34798 discloses this type of camera. The methods described in Japanese Laid-Open Patent Publications Nos. H4-26832 and H5-34798 enable a leaked magnetic flux of a certain intensity to be shielded according to the BH characteristics and relative permeability of the shielding member.
However, with the shielding devices described in the above-noted Japanese Laid-Open Patent Publications it is possible to shield only the leaked magnetic flux having a certain intensity that is particular to the shielding member. More particularly, the intensity of the leaked magnetic flux from the motor changes according to the rotation of the motor between a minute magnetic field intensity and a high magnetic field intensity with a certain frequency. Thus, it is not possible to effectively shield the leaked magnetic flux with a thin shielding member if the magnetic field intensity periodically fluctuates.